// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package org.apache.doris.common.security.authentication;

import org.apache.hadoop.security.UserGroupInformation;

import java.io.IOException;
import java.util.Objects;

public class ImpersonatingHadoopAuthenticator implements HadoopAuthenticator {

    private final HadoopAuthenticator delegate;
    private final String username;
    private UserGroupInformation ugi;

    public ImpersonatingHadoopAuthenticator(HadoopAuthenticator delegate, String username) {
        this.delegate = Objects.requireNonNull(delegate);
        this.username = Objects.requireNonNull(username);
    }

    @Override
    public synchronized UserGroupInformation getUGI() throws IOException {
        if (ugi == null) {
            ugi = UserGroupInformation.createProxyUser(username, delegate.getUGI());
        }
        return ugi;
    }
}
